This invention relates to improved, explosive compositions. In another aspect, this invention relates to improved explosive compositions comprising readily available, highly combustible liquid fuels and a supported air entrapment material. In yet another aspect, this invention relates to a method for rendering highly combustible liquids explosive and sensitive to a number six blasting cap, by combining the liquids with supported air entrapment materials.
Explosive compositions are widely used in our industrial society. Probably the best known explosive composition is dynamite, which was invented by Nobel. Dynamite utilizes a very dangerous precursor material, namely liquid nitroglycerin, which is already a cap-sensitive explosive, and thereafter, combines it with various fillers to make it a relatively safe material to handle. However, the production and handling of dynamite is still hazardous because to the highly explosive nature of the dynamite components.
Many alternative explosive compositions have been suggested to replace dynamite and other hazardous explosives. For example, relatively safe materials, such as nitroparaffins and the like, have been found to be easily sensitized to become excellent performing explosives with high power and energy release. Nitroparaffins, such as nirtromethane, can be rendered cap-sensitive by several approaches, including the addition of microspheres of entrapped air in a gel of the nitroparaffins, such as is disclosed in Minnic, U.S. Pat. No. 3,338,165. This approach may produce a cap-sensitive explosive composition, but it has been found that gels are very difficult to produce and do not remain stable under long term storage conditions or under temperature fluctuations, as may be expected in some field operations.
Other approaches for rendering materials such as nitroparaffins cap-sensitive have been to incorporate air entrapment materials, such as microspheres and the like in a foam precursor system, followed by a foaming step. After the foam has been sufficiently cured, nitroparaffins can be added to the foam. This approach has been suggested by such references as Chandler, U.S. Pat. No. 3,794,534, and Eckels, U.S. Pat. No. 3,797,392. These approaches for producing explosive compositions have not met with commercial success on a wide scale because of the extreme difficulty in production of the foamed materials having evenly distributed air entrapment materials therein. In many instances, materials made by these processes will not even detonate. Additionally, when detonation can be achieved, there is very little reliability in the performance of such compositions.
Many other methods have been suggested for rendering combustible liquids, such as nitroparaffins, capsensitive, including the addition of nitroparaffins to finely ground materials such as carbonaceous materials, oxidizer materials, such as ammonium nitrate and the like. Many different references, such as Hearst, U.S. Pat. No. 3,718,512, Davidson, U.S. Pat. No. 2,892,377, and others, discuss the advisability of finely grinding materials such as ammonium nitrate and thereafter very closely and precisely controlling the amount of a nitroparaffin, such as nitromethane, that is added to the finely ground ammonium nitrate material. While such mixtures can be utilized for explosive materials, many problems and disadvangtages are connected with such teachings in the prior art. For example, the amount of the nitromethane that is added to the composition must be very closely controlled. Additionally, such compositions do not store well and will lose their sensitivity over reasonable periods of storage. In fact, many of the explosives must be field prepared utilizing relatively time-consuming procedures. It has also been found that such explosive materials, even when they can be successfuly prepared and detonated, do not have extremely high levels of explosive energy, thereby requiring the use of additional pounds of explosive to achieve a desired result.
Methods for sensitizing nitroparaffins by the addition of various soluable amines and acids have also been suggested by numerous references in the prior art. These explosives are very powerful and efficient but, unfortunately, they all lack long-term storage stability and must be used within a matter of a few hours or a few days after mixing.
In view of the foregoing, it is highly desirable to produce an inexpensive and easily prepared explosive composition from highly combustible, safe liquid materials and other inexpensive solid materials. The inventor is well aware of the problems of prior art explosive compositions and is well aware of the need for the production of inexpensive explosive compositions that can be safely and easily prepared and stored over a long period of time without losing their sensitivity to detonation.